Paul, an apostle of Jesus Christ by the commandment of God our Saviour, and Lord Jesus Christ, which is our hope;
An apostle of Jesus Christ - belonging to Him as His servant. Paul thus designates himself in an official letter; but in a personal letter (Philem), "a prisoner of Jesus Christ."
By the commandment of God - the authoritative injunction х epitageen (G2003)], as well as commission, of God. In the earlier letters, "by the will of God." Here the phrase implies a necessity laid on him to act as an apostle: not a matter of option. The same expression occurs in the doxology in Romans 16:26.
God our Saviour - the Father (1 Timothy 2:3; 1 Timothy 4:10; Luke 1:47; 2 Timothy 1:9; Titus 1:3; Titus 2:10; Titus 3:4; Jude 1:25): a Jewish expression in devotion, from the Old Testament (cf. Psalms 106:21).
Our hope - the object, substance, and foundation of our hope (Colossians 1:27; Titus 1:2; Titus 2:13).